Source : Webster's Revised Unabridged Dictionary (1913)

Emery \Em"er*y\, n. [F. ['e]meri, earlier ['e]meril, It.
   smeriglio, fr. Gr. ?, ?, ?, cf. ? to wipe; perh. akin to E.
   smear. Cf. {Emeril}.] (Min.)
   Corundum in the form of grains or powder, used in the arts
   for grinding and polishing hard substances. Native emery is
   mixed with more or less magnetic iron. See the Note under
   {Corundum}.

   {Emery board}, cardboard pulp mixed with emery and molded
      into convenient.

   {Emery cloth} or {paper}, cloth or paper on which the powder
      of emery is spread and glued for scouring and polishing.
      

   {Emery wheel}, a wheel containing emery, or having a surface
      of emery. In machine shops, it is sometimes called a {buff
      wheel}, and by the manufacturers of cutlery, a {glazer}.

Source : WordNet®

emery
     n : a hard gary-black mineral consisting of corundum and either
         hematite or magnetite; used as an abrasive (especially as
         a coating on paper)